Marks on the genetic 'code' that babies have at birth is different for children who go on to be obese or overweight compared to those who do not, new research has found.

Using blood from 178 babies' umbilical cord, researchers from Newcastle and Bristol universities analysed genes that are known to be linked to body weight and found that nine of the 24 relevant genes looked at in this study were linked to the child's weight at age nine. The findings are published in PLoS ONE.

Dr Caroline Relton, senior lecturer in epigenetic epidemiology at Newcastle University, who led the work said: "We were looking at the epigenetic patterns, the regulatory marks on genes. In this research we found a link between those found at birth and differences in body composition in children when they were nine.

"This suggests that our DNA could be marked before birth and these marks could predict our later body composition."

Epigenetics is a rapidly emerging and exciting area of scientific research which may help us to explain how the environment and genome work in concert to influence our risk of many diseases. Evidence is growing that factors like diet, exercise, smoking and hormones can alter the regulation of our genome - when genes are switched on and when they are switched off - even before birth.

There is growing scientific evidence to show that adverse factors during development in the womb, such as a poor diet, maternal smoking or stress, predispose you to obesity and other health problems. Epigenetics is a mechanism that might explain how this comes about because epigenetic markings can be influenced by our environment and behaviours. The findings from this study support this idea.

This research identified genes that showed different patterns of expression in children who were overweight or obese compared to children of normal weight. Epigenetic patterns (DNA methylation) were then analysed in these genes in DNA samples from children collected at birth to assess whether there was any evidence that these genes are somehow different well before childhood body composition is developed.

This investigation used data from two studies of children who have been followed up over several decades. The Avon Longitudinal Study of Children and Parents, in which pregnant women were recruited over two decades ago, provided the basis, building on its unique collection of biological samples linked to questionnaire and clinical examination data over a 21 year period. The second was a  Newcastle based study of children who were born preterm and followed up during childhood with multiple measures including growth, neurodevelopment and metabolic health.

Dr Relton added: "While we have discovered an association between these genes and body size in childhood we need to carry out further studies to establish whether influencing the expression of these genes by altering epigenetic patterns is indeed a trigger to obesity."

For a video about the research see here.

Reference:  DNA methylation patterns in cord blood DNA and body size in childhood", PLoS ONE PONE-D-11-14003R1 10.1371/journal.pone.0031821

published on: 14 March 2012